PIK3CA and gastric cancer: For instance, some gastric cancer (GC) cases have shown a high transcriptional and translational expression of the PI3K/AKT/mTOR pathway, with a mild overexpression of PIK3CA, PIK3CB, AKT1, MTOR, RPS6KB1, EIF4EBP1, and EIF4E genes, along with a slightly decreased expression of PTEN and TSC1 gene in GC tissues compared to adjacent non-tumoral tissues [18].